Device for fabricating a metalized film capacitor

ABSTRACT

A metallized film capacitor formed by laminating or winding a metallized film 1 with metal evaporated electrode on one or both sides thereof so that a pair of metal evaporated electrodes 2 are opposite to each other, wherein electrode lead-out portions 3 are provided at both ends of the capacitor, each metal evaporated electrode is composed of a low resistance area abutting on the electrode lead-out portion and a remaining high resistance area having higher resistance than it, a split electrode pattern with a plurality of minute blocks 8 formed in a longitudinal direction and width direction and fusing areas 9 between the adjacent minute blocks is formed on at least one of the metal evaporated electrodes, and electrode partitioning lines 7 are formed at regular intervals in a longitudinal direction of the film. The metallized film is fabricated by depositing substance such as oil for preventing evaporation of metal on the evaporation side of a plastic film 10 through a rotary screen cylinder with any pattern formed by mesh processing and immediately thereafter depositing evaporated metal, thereby forming a split fuse pattern serving as a safeguard mechanism during high speed evaporation.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a divisional of U.S. patent application Ser.No. 08/907,902 filed on Aug. 11, 1997, now U.S. Pat. No. 5,905,628.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a metallized film capacitor forimproving power factor, an electric appliance, several kinds of powersource circuit and communication device, a device and method forfabricating a metallized film used for the metallize film capacitor.

2. Description of the Related Art

Conventionally, a capacitor equipped with a fusing mechanism by minutedivision of evaporated metallized film or using the metallized film isdisclosed in Japanese Patent Unexamined Publication Nos. Hei 4-225508,Hei 8-31690, etc. Therefore, it is possible to fabricate a metallizedfilm capacitor equipped with the fusing mechanism.

A previously known method of fabricating a metallized film for acapacitor is shown in FIG. 13. In this method, as shown in FIG. 16,immediately before an evaporated metal 15 is evaporated, in a vacuumevaporator, on a plastic film 10 (high polymer film) at a position wherethe film is brought into contact with a cooling roll 12, it is passedthrough an oil depositing device so that a plurality of divided marginsserving as a safeguard mechanism is formed in a longitudinal directionof the plastic film (Japanese Patent Unexamined Publication No. Hei57-152122). The apparatus used for this purpose includes an oil tank 14that contains oil 27 therein and a shutter 28 rotating around the oiltank 14. The oil 27 within the oil tank 14 is heated and vaporized. Whenan opening 31 of the oil tank 14 and another opening 30 of the rotatingshutter 28 coincide with each other, the oil passes through the openings31 and 30 to be deposited on the plastic film 10. In this case, sincethe rotating shutter 28 rotates in synchronism with the supplying speedof the plastic film 10, the oil 27 can be deposited on the plastic tapeat regular widths and intervals.

Another previously known method for fabricating a metallized film isshown in FIG. 14. In this method, a convex type roll 33 with protrusions32 formed on its circumference at given positions is used. A metalevaporation preventing substance (e.g. oil) 27 deposited on the surfaceof the protrusions 32 are transferred onto a plastic film 10 to formnon-evaporated portions (Japanese Patent Unexamined Publication No. Hei6-158271) thereon. Still another previously known method for fabricatinga metallized film is shown in FIG. 15. In this method, using a concavetype roll 35 with grooves 34 formed on its circumference, a metalevaporation preventing substance (e.g. oil) deposited on the surface ofthe grooves 34 are transferred onto the plastic film 10 to formnon-evaporated portions thereon (Japanese Patent Unexamined PublicationNo. Hei 4-346652).

A further previously known method for fabricating a metallized film isshown in FIG. 11. In this method, in an evaporation step, margins of atape at regular widths and intervals are evaporated in a directionparallel in the longitudinal direction of the tape by the oil maskingtechnique and-tape margin technique, and in a post step, a plurality ofdivided electrodes and fuse portions are formed in the longitudinaldirection by laser trimming and discharge machining.

The metallized film capacitor fabricated by the methods as describedabove suffers from several problems. In a configuration shown in FIG. 11in which a metallized electrode is divided into plural minute blocks 8and fuse areas 9 are arranged between the blocks, where minute breakagewhich cannot be cleared by self-recovery occurs, an excessiveshort-circuiting current flows so that the pertinent fuse area 9operates to separate the broken portion from the metallized filmcapacitor. But since its area is minute, the current circulating frombetween the adjacent minute blocks causes the fuse area therebetween tobe also operated, thus reducing the capacitance of an non-problematicportion.

Further, where the fuse area 9 does not operate by the short-circuitingcurrent by clearing the minute breakage, the breakage at the blockcontinues to lead to dielectric breakdown. Further, the breakage mightspread toward the surrounding blocks. In the worst case, the metallizedfilm capacitor might catch smoke or fire.

Further, as shown in FIG. 12, in the metallized film capacitor equippedwith a safeguard mechanism, in many cases, in order to improve thecontact force between a metal sprayed area serving as an electrodelead-out portion and a metallized film, the thickness of an evaporatingfilm at the metal sprayed area side is made thicker whereas that of theremaining portion is made thinner. At least one of the evaporating filmsis divided by electrode partitioning lines 7 to form the fuse area 9. Inthis case, the safeguard mechanism, when the breakage that cannot becleared by self-recovery which is inherent to a film capacitor occurs,serves to operate the fuse area 9 using the Joule heat of theshort-circuiting current for clearing the broken portion. But, where thebreakage which cannot be cleared because of the thick film evaporated inthe metal sprayed area, which requires higher energy for its clearingthan the remaining portion does, the short-circuiting current continueto flow. Thus, the dielectric breakdown might occurs at the thickevaporated film.

However, the techniques for forming the non-evaporated portion sufferfrom several problems to be solved.

Where the metallized film capacitor with the safeguard mechanism is tobe fabricated using the rotary shutter 28 as shown in FIGS. 13 and 16,as the case may be, in view of the property of a capacitor, theelectrode of the evaporated film must be not only divided in pluralblocks in a longitudinal direction of the plastic film, but also asquare non-metallic island (fuse area) must be simultaneously formed ineach of the divided electrode blocks. In this case, when the dividedblocks and fuse areas are to be formed using the rotary shutter 28, onlythe slender fuse areas in the width direction of the film serve as relayportions of the rotary shutter 28. When the evaporation is carried outat a high speed, therefore, the rotary shutter 28 is apt to be deformedand the divided blocks and fuse areas are likely to be unclear. For thisreason, the speed of evaporation could not be increased. Further, if ameans is adopted which uses a difficult-to-deform substance forpreventing the rotary shutter 28 from being deformed and increase thethickness, workability is deteriorated because of the problem of weight.In addition, in this case, the margin in a longitudinal direction mustbe formed at a separate portion by the oil masking method and tapemargin technique. The adjustment required therefor might deteriorate theworkability further greatly.

The technique using the convex type roll 33 as shown in FIG. 14 providesthe following problem occurs. When the metal evaporation preventingsubstance (e.g. oil) 27 is deposited to the protrusions 32 to form thenon-evaporated margin, i.e. island-like divided electrode are formed inthe longitudinal direction of the plastic film 10 and provide theelectrodes with a fusing function, because of the centrifugal force ofthe convex type roll 33, the oil 27 scatters to provide a spot-likeevaporated film and blur of the margin. This make it impossible toincrease the evaporation speed.

The technique using the concave type roll 35 permits the evaporationspeed to be increased. However, this technique has disadvantages thatthe cost of the concave type roll (pattern roll) 35 is expensive, andattachment/detachment of the concave type roll 35 in exchange isdifficult owing to the problem of weight.

The technique shown in FIG. 13, in which in an evaporation step, marginsare evaporated at regular widths and intervals in a direction parallelin the longitudinal direction of the tape and in a post step, aplurality of divided electrodes and fuse areas are formed in thelongitudinal direction by laser trimming and discharge machining,provides economical and time loss because of an additional one step ascompared with the other techniques.

SUMMARY OF THE INVENTION

The present invention has been made to solve the above problems, and anobject of the invention is to provide a metallized film capacitor thatimproves in characteristic.

Another object of the invention is to provide an apparatus and methodfor fabricating a metallized film used for the metallized filmcapacitor, which is capable of applying oil for preventing evaporationof evaporated metal at a high speed and sufficiently.

In order to attain the above object, according to a first aspect of theinvention, there is provided a metallized film capacitor which is formedby laminating or winding a metallized film with metal evaporatedelectrode on one or both sides thereof so that a pair of metalevaporated electrodes are opposite to each other, wherein electrodelead-out portions are provided at both ends of the capacitor, each metalevaporated electrode is composed of a low resistance area abutting onthe electrode lead-out portion and a remaining high resistance areahaving higher resistance than it, a split electrode pattern with aplurality of minute blocks formed in a longitudinal direction and widthdirection and fusing areas between the adjacent minute blocks is formedon at least one of the metal evaporated electrodes, and electrodepartitioning lines are formed at regular intervals in a longitudinaldirection of a film.

In the second metallized film capacitor according to a second aspect ofthe invention, in addition to the first aspect, the area of each of theminute blocks in said low resistance film area is smaller than that inthe high resistance area.

In the metallized film capacitor according to a third aspect of thepresent invention, in addition to the second aspect, the evaporatedmetal is made of zinc or zinc/aluminum alloy.

The device for fabricating a metallized film capacitor according to afourth aspect of the present invention comprises means for vaporizing ametal evaporation preventing agent preventing evaporated metal frombeing evaporated on a film and a screen with an evaporated pattern,wherein a vaporized metal evaporation preventing agent is depositeddirectly on film through said screen.

In the device for fabricating a metallized film capacitor according to afifth aspect of the present invention, said screen is a mesh havingopenings.

In the device for fabricating a metallized film according to a sixthaspect of the present invention, each of the openings of the mesh has adiameter of 10 μm to 1 mm.

The device for fabricating a metallized film according to a seventhaspect of the present invention comprises temperature-holding means forholding the vaporized state of said metal evaporation preventing agentuntil it reaches the film.

The device for fabricating a metallized film according to an eighthaspect of the present invention comprises means for driving the screenat a speed in synchronism with the shifting speed of the film.

In the device for fabricating a metallized film according to a ninthaspect of the present invention, said screen is cylindrical.

In the device for fabricating a metallized film according to a tenthaspect of the present invention, said film is shifted along acylindrical face.

The device for fabricating a metallized film according to an eleventhaspect of the present invention comprises distance adjusting means foradjusting a distance between said screen and a discharging opening ofsaid metal evaporation preventing agent.

The device for fabricating a metallized film according to a twelfthaspect of the present invention comprises an impression cylinder rollfor defining the passage of said film oppositely to said screen withrespect said film.

In the device for fabricating a metallized film according to athirteenth aspect of the present invention, said film is shifted alongthe curve of an impression roll.

The device for fabricating a metallized film according to a fourteenthaspect of the present invention comprises means for adjusting thedistance between said impression cylindrical roll and said screen.

In the device for fabricating a metallized film according to a fifteenthmeans of the present invention, a deposited pattern of said screen has asplit margin and fuse area which constitute a safeguard mechanism.

A method of fabricating a metallized film capacitor according to thepresent invention comprises a first step of vaporizing a metalevaporation preventing agent for preventing evaporated metal from beingevaporated on a film; a second step of depositing said vaporized metalevaporation preventing agent vaporized by said vaporizing means directlyon said film through a screen to a clear pattern on a margin at a highspeed; and a third step of depositing said evaporated metal on saidfilm.

In the configuration described above, in the metallized film capacitoraccording to the first aspect of the present invention, a splitelectrode pattern with a plurality of minute blocks formed in alongitudinal direction and width direction and fusing areas between theadjacent minute blocks is formed on one metal evaporated electrode, andelectrode partitioning lines are formed at regular intervals in alongitudinal direction of a film. For this reason, where minute breakagewhich cannot be cleared by self-recovery occurs in a plurality of minuteblocks, reduction in capacitance resulting when the current flowing frombetween adjacent minute blocks operates the non-problematic fusing areabetween the blocks can be suppressed. Also where the fusing area doesnot operate because of the short-circuiting current due to clearing ofminute breakage, breakage in the capacitor can be prevented whichresults from the breakage at the block continuing to lead to dielectricbreakdown and to spread toward the surrounding blocks.

Further, the metallized film according to the second aspect of thepresent invention, in addition to the first aspect, has improved theclearing of the minute broken area because the minute block in the lowresistance film area abutting on the electrode lead-out portion has asmaller area than the other portion, thereby improving the operabilityof the fusing portion. For this reason, as regards the breakage whichcannot be cleared when the evaporated film on the side of the flamesprayed potion, the short-circuiting current continues to flow toprevent the dielectric breakage from occurring at the thick portion ofthe evaporated film.

The film capacitor according to the third aspect of the presentinvention, in addition to the second aspect, uses zinc or zinc/aluminumalloy as the evaporated metal. For this reason, using the metalcharacteristic of these metal which does not require larger energy toperform clearing in minute breakage than a single element of aluminumwhich is mainstream of the metallized film capacitor at present, higherpotential or miniaturization of the metallized film capacitor can berealized than the aluminum evaporated capacitor.

The above and other objects and features of the present invention willbe more apparent from the following description taken in conjunctionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional schematic view of a metallized film capacitoraccording to an embodiment of the present invention;

FIG. 2 is a partial plan view of the one metallized film according tothe embodiment;

FIG. 3 is a partial plan view with a different split electrode patternaccording to the embodiment;

FIG. 4 is a partial plan view with another split electrode patternaccording to the embodiment;

FIG. 5 is a partial plan view of the other metallized film according tothe embodiment;

FIG. 6 is a view showing a device for fabricating a metallized filmaccording to another embodiment according to the present invention;

FIG. 7 is a view showing an example of a metallized film fabricated bythe device;

FIG. 8 is a view showing a screen cylinder used in the device;

FIG. 9 is an enlarged view of a screen part of the cylinder;

FIG. 10 is a view for explaining an internal conduit and an oil nozzlein the screen cylinder;

FIG. 11 is a partial plan view of the one metallized film according to asecond prior art;

FIG. 12 is a partial plan view of the one metallized film with adifferent electrode pattern according to a first prior art;

FIG. 13 is a view explaining a first conventional fabricating device fora metallized film;

FIG. 14 is a view explaining a second conventional fabricating devicefor a metallized film;

FIG. 15 is a view explaining a third conventional fabricating device fora metallized film; and

FIG. 16 is a view explaining a fourth conventional metallized film for ametallized film.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, a description will be given in more details of preferredembodiments of the present invention with reference to the accompanyingdrawings.

Now referring to FIGS. 1 to 5, an explanation will be given of anembodiment of the present invention.

Reference numeral 1 denotes a dielectric film of a plastic film.Reference numeral 2 denotes a metal evaporated electrode in which analloy of zinc and aluminum is deposited on a mesh-like divided electrodepattern shown in FIGS. 2, 3 or 4 using a continuous vacuum evaporator.Reference numeral 2a denotes a metal evaporated electrode having nodivided electrode pattern as shown in FIG. 5. Reference numeral 3denotes one of electrode lead-out portions metal-frame sprayed on bothends of the capacitor formed by laminating or winding a pair of themetallized film having the divided electrode pattern and the metallizedfilm having no divided electrode pattern. Reference numeral 4 denotesone of the low resistance areas of the evaporated electrodes 2, 2a whichhave lower resistance than the remaining areas and abut on the electrodelead-out portions 3. Reference numeral 5 denotes one of high resistancefilm areas of the evaporated electrodes 2 and 2a. Reference numeral 6denotes one of electrode margins formed at one ends of the highresistance film areas 5. Reference numeral 7 denotes one of electrodepartitioning lines each of which partitions the metal evaporatedelectrode 2 at regular intervals in the longitudinal direction of thefilm. The electrode partitioning lines 7 may a straight line (FIGS. 2and 3) or saw-tooth polygonal line.

Reference numeral 8 denotes one of minute blocks of the mesh-likedivided electrode pattern of the metal evaporated electrode 2. Theseblocks are plural areas formed in the longitudinal and width directionsof the film through fuse areas.

Reference numerals 8a and 8b are minute blocks adjacent to the electrodelead-out portions 3. The minute blocks 8a and 8b, the area of each ofwhich is smaller than that of each of the minute blocks 8, promotesclearing of minute broken areas and improves the operation of the fuseareas 9.

In this way, the metallized film capacitor according this embodimentincludes a metallized film with the metal evaporated electrode 2 dividedinto minute blocks 8 in the longitudinal and width directions, fuseareas 9 formed between the adjacent minute blocks and electrodepartitioning lines 7 formed at regular intervals in the longitudinaldirection of the film 1; and another metallized film with the metallizedevaporated electrode 2a with no minute blocks and partitioning lines. Itshould be noted that a pair of metallized films 2 and 2a both with themetal evaporated electrodes each divided into plural minute blocks 8 maybe laminated or wound to form a metallized film capacitor.

In this embodiment, the minute blocks 8a, 8b of the low resistance filmarea 4 in contact with the electrode lead-out portion 3, each of whichhas a smaller area than that of the remaining high resistance area 5,can promote the clearing of the minute broken portion and improve theoperation of the fuse area 9.

In the embodiment, the metal evaporated electrodes 2, 2a are made ofzinc or zinc/aluminum alloy. For this reason, using the metalcharacteristic of these metal which does not require larger energy toperform clearing in minute breakage than a single element of aluminumwhich is mainstream of the metallized film capacitor at present, higherpotential or miniaturization of the metallized film capacitor can berealized than the aluminum evaporated capacitor.

The fourth fabricating device for a metallized film according to thepresent invention deposits a vaporized metal evaporation preventingagent directly on film through a screen to a clear pattern on a marginat a high speed.

The fifth fabricating device for a metallized film can hold the strengthof the screen to prevent the distortion when the screen is rotated.

The six fabricating device for a metallized film can from a pattern withno clogging accurately.

The seventh fabricating device for a metallized film can hold thevaporized state of a metal evaporation preventing agent until it reachesa film, thereby forming a clear pattern.

The eighth fabricating device for a metallized film makes the shiftingspeeds of a screen and a film synchronous with each other so that thedisplacement or blue of the pattern can be suppressed.

The ninth fabricating device for a metallized film, in which a screen iscylindrical, can easily the screen and will not injure the film.

The tenth fabricating device for a metallized film shifts the film alonga cylindrical face so that the contact between a screen and a film canbe held without using a specific means for holding the film.

The eleventh fabricating device for a metallized film can provide adistance between an optimum screen and a discharging opening of a metalevaporation preventing agent in accordance with the kind of oil to beused, shifting speed, kind of a pattern, etc.

The twelfth fabricating device for a metallized film can prevent thechattering of a film by an impression cylinder roll, thereby forming apattern accurately.

The thirteenth fabricating device for a metallized film can shift a filmalong the impression cylinder roll so that the film is brought intocontact with the impression roll, thereby keeping the distance betweenthe screen and film.

The fourteenth fabricating device for a metallized film adjusts thedistance between the impression cylinder roll and the screen so that thedistance between the screen and the film can be adjusted.

The fifteenth fabricating device for a metallized film can form a splitmargin and fuse area with no succeeding step.

The method of fabricating a metallized film deposits the vaporized metalevaporation preventing agent the fourth fabricating device for ametallized film directly on a film through a screen to a clear patternon a margin at a high speed.

Embodiment 1

With reference to concrete numerical values, a detailed explanation willbe given of embodiments of the present invention. As an example No. 1,using a continuous vacuum evaporator, an alloy of zinc and aluminum wasevaporated on a polypropylene film having a thickness of 6 μm. With theevaporated film having resistance of 2-8 Ω/^(H) T at the metal-framespraying area and of 10-30 Ω/^(H) T, a winding capacitor was fabricatedwhich has a pair of metallized films with the divided electrode pattern(FIG. 2) and with no divided electrode pattern (FIG. 5). Likewise, as anexample No. 2, another winding capacitor was fabricated which has a pairof metallized films with the divided electrode pattern (FIG. 3) and withno divided electrode pattern (FIG. 5). For comparison, prior art windingcapacitors 1 (FIG. 12) and 2 (FIG. 11) were also fabricated.

The AC voltage step-up test was carried out at a maximum permissibletemperature and another temperature higher by +15° C than it. The testresult is shown in Table 1.

                  TABLE 1                                                         ______________________________________                                               Max Permissible Temp.                                                                       Max Permissible Temp.                                           (° C.) (° C.) +15° C.                             ______________________________________                                        Example I                                                                              10/10           10/10                                                         Safegard Mechanism                                                                            Safegard Mechanism                                            Operation       Operation                                            Example II                                                                             10/10           10/10                                                         Safegard Mechanism                                                                            Safegard Mechanism                                            Operation       Operation                                            Prior Art I                                                                            10/10           4/10                                                          Safegard Mechanism                                                                            Safegard Mechanism                                            Operation       Operation                                            Prior Art II                                                                           10/10           8/10                                                          Safegard Mechanism                                                                            Safegard Mechanism                                            Operation       Operation                                            ______________________________________                                    

In the voltage step-up test, a voltage was boosted by 50 V for each 12hours from the rated voltage under the maximum permissible temperature.When the electrostatic capacitance becomes approximately zero, it wasjudged that the safeguard mechanism had been operated. In this case, thesafeguard mechanism was operated for all the capacitors according to theexamples Nos. 1 and 2. Thus, no difference in the capacitorcharacteristic was not produced. Therefore, the same test was carriedout at an environmental temperature increased by 15° C. from the maximumpermissible temperature.

At the maximum permissible temperature plus 15° C., in all the samplesaccording to the examples Nos. 1 and 2, the safeguard mechanism wasoperated whereas in the samples according to the prior art No. 1, sixsamples were broken and in the samples according to the prior art No. 2,two samples were broken. In the samples of the prior art No. 1, both thethick area (frame sprayed area) and the thin area (center area) werebroken. In the sample of the prior art No. 2, only the thick area wasbroken. From this test result, it can be guessed that the breakage atthe thick area (metal-frame spraying area) results from that thebreakage at this area cannot be cleared because of higher energyrequired for clearing than the remaining area and hence theshort-circuiting current continues to flow so that excessive heat wasgenerated at the fuse areas, leading to dielectric breakdown. It can bealso guessed that the breakage at the thin area (center area) resultsfrom that the short-circuiting current due to the clearing of minutebreakage does not operate the fuse area and hence the breakage continuesat the pertinent block so that the dielectric breakdown spreads towardthe surrounding blocks, thus leading to breakdown of the capacitoritself.

On the other hand, it can be guessed that the capacitors according tosample Nos. 1 and 2 have not been broken for the reasons why the lowresistance film area in contact wit the electrode lead-out portion 3, inwhich the area of the minute block is smaller than the remaining area,has improved the clearing of the minute breakage and the operability ofthe fuse area, thereby leading to the safeguard mechanism; and that theelectrode partitioning lines formed at regular intervals in thelongitudinal direction prevent the breakage at the minute block 8 fromcontinuing to spread toward the surrounding blocks.

As regards the same samples, the self-recovery test described in JIS4908was carried out. The test result was shown in Table 2.

                  TABLE 2                                                         ______________________________________                                                 Changing Rate of Electrostatic Capacitance                                    ΔC/C (%)                                                       ______________________________________                                        Example I  -0.1 -0.2 -0.2 -0.3 -0.3                                                                       X = -0.22                                         Example II -0.1 -0.1 -0.1 -0.2 -0.2                                                                       X = -0.14                                         Prior Art I                                                                              -0.5 -0.7 -0.7 -0.8 -1.0                                                                       X = -0.74                                         Prior Art II                                                                             -0.3 -0.3 -0.4 -0.5 -0.6                                                                       X = -0.42                                         ______________________________________                                    

As seen from the table, the prior art sample No. 1 has indicated alarger changing rate of the electrostatic capacitance than in theexamples Nos. 1 and 2. It can be guessed that this is because the priorart sample No. 1 has the-divided electrode area larger than the minuteblock area, the fuse is fused by the short-circuiting current inself-recovery.

On the other hand, the prior art sample No. 2 has also indicated alarger reduction in the capacitance than the sample Nos. 1 and 2. Itseems that this is because the current flowing from between the adjacentblocks in self-recovery of a certain block has operated the fusing areabetween the adjacent blocks which are not problematic. On the otherhand, in the samples Nos. 1 and 2, the partitioning lines formed atregular intervals in the longitudinal direction of the film suppress theflowing current in the self-recovery to suppress the fusing operation ofthe minute block which is not problematic so that th meaninglessreduction of the capacitance has been could be prevented.

Additionally, when the self-recovery has occurred at the low resistancefilm area 4 in contact with the electrode lead-out portion 3, because oflarge energy of the self-recovery, in almost all cases, the fuse wasoperated, thus leading to reduction of the capacitance. In the sampleNo. 2, considering this, in the low resistance area 4 abutting on theelectrode lead-out portion 3, the minute blocks 8a, 8b are divided intomore minute areas, thereby suppressing reduction of the capacitance.

Embodiment 2

FIG. 6 is a view showing an apparatus for fabricating a metallized filmaccording to one embodiment of the present invention. FIG. 7 is a viewshowing an example of the metallized film fabricated by the fabricatingapparatus. FIG. 8 is a view showing a screen cylinder used in theapparatus. FIG. 9 is an enlarged view of a screen section thereof. FIG.10 is a view explaining an inner conduit and oil nozzle of the screencylinder. In these figures, reference numeral 10 denotes a plastic film;11 denotes a vaporized oil gas which flows through a oil gas flow pathfrom an oil tank 14 and is jet out from the inside of a screen cylinder13 with a screen formed toward the plastic film 10. Reference numeral 16denotes an evaporation source which heats metal to be evaporated anddeposits the metal on the plastic film 10. Reference numeral 12 denotesa cooling roll; 24 an oil nozzle and 25 a supply roll; and 26 a patternportion.

Reference numeral 18 denotes a margin; 19 a split margin; 20 anevaporated film (active portion); 21 a fuse area; 22 a window margin and23 an evaporated film (heavy edge portion).

In a vacuum evaporator which can evaporate zinc in a heavy-edge shape onthe one side of a polypropylene film having a thickness of 6 μm, asafe-guard pattern as shown in FIG. 7 is formed before the plastic film10 supplied from the supply roll 25 passes the cooling roll 12. Thetypical pattern as shown in FIG. 7 is basically composed of minute areasinto which the evaporated film is divided. A pattern portion made on thescreen cylinder 13 must be mesh-shaped.

If the pattern portion 26 is not mesh-shaped but punched out, the margin18 cannot be formed in the longitudinal direction of the film but formedby another technique. The pattern as shown in FIG. 7, in which only thefuse areas 21 serves as connecting portions, becomes weak in strengthbecause the screen cylinder 13 rotates at a high speed. Further, thescreen cylinder 13, which is used within the evaporator, must becylindrical. The screen cylinder must not be plane-shaped to realize acontinuous manner. Further, it must not be polygonal not so as to injurethe plastic film.

The diameter of each of openings of the mesh pattern is preferably 10 μmto 1 mm. This is because when it is smaller than 10 m, clogging is aptto occur whereas it exceeds 1 mm, the fusing accuracy will bedeteriorated.

The oil gas 11 is heated and vaporized in the oil tank 14 outside thescreen cylinder 13 and passes through the oil gas path 17 which isheated (heating portion is not shown). The oil gas while being vaporizedis guided to the tip of the oil nozzle 24 which is an oil gas jettinginlet. Further, the oil gas passes through the patterned screen cylinder13 from the tip of the oil nozzle 24 and deposited onto the plastic film10. If the oil gas flow path is not heated, the oil gas 11 vaporized inthe oil tank 14 is liquefied. To prevent this, the heating is carriedout for the path to the oil nozzle 24.

The screen cylinder 13, oil nozzle 24, oil tank 14 and oil-gas flow pathare arranged as shown in FIG. 10. The width of the screen cylinder 13 ismade larger than that of the plastic film 10 which is a base material.The width of the oil nozzle 24 is made equal to that of the screencylinder 13. The end of the oil nozzle 24 has a shape along the curve ofthe inner wall of the screen cylinder 13 which is cylindrical. With thetip abutting on the inner wall of the screen cylinder 13, the depositionis carried out.

The plastic film 10 which is a base material, while it is partially madeto abut on the cylindrical surface of the screen cylinder 13, istransferred. The screen cylinder 13 itself is also driven (the drivingmeans is not shown) in synchronism with the plastic film 10. The isbecause if the deposition is carried out without driving the screencylinder 13, the plastic film 10 will slip on the surface of the screencylinder 13, thus making it impossible to assure the pattern accuracyand clearness.

Since the oil nozzle 24 is caused to abut on the inner wall of screencylinder 24 on which the plastic film 10 abuts partially, the oil can bedeposited surely, thus making the clear pattern.

In this embodiment, the deposition was carried out with the oil nozzle24 abutting on the internal wall of the screen cylinder 13, according tothe pattern to be formed, the presence of a slight gap is desiredbetween the oil nozzle 24 and the internal wall of the screen cylinder.Therefore, the oil-nozzle 24 preferably has gap adjusting means (notshown).

The safeguard mechanism pattern, as shown in FIG. 7, includes band-likemargins 18 in a longitudinal direction of the film and split-margins 19and fusing areas 21 which serve as safeguard mechanism in a metallizedfilm capacitor.

In this embodiment, deposition was carried out at two speeds of 300m/min and 600 m/min. In The metallized film pattern shown in FIG. 7, thewidth of the margins 18 was set at 4 mm, that of the split margins 19and window margins 22 was set at 0.5 mm, and that of the fusing areas 21was set at 0.8 mm. For comparison, the metallized film was also formedin attachment of a rotary shutter having a safeguard mechanism pattern(comparative example No. 1). Further, it was also formed in a manner oftransferring oil using a pattern roll having protrusions attached inplace of the screen cylinder (comparative example No. 2). For depositionof the Yheavy edge, the film resistance of the active area was set at10-20 Ω/□ and that of the heavy edge area was set at 3-5 Ω/□.

                  TABLE 3                                                         ______________________________________                                                   300 m/min.  600 m/min.                                                        Split  Window   Split    Window                                               Margin Margin   Margin   Margin                                    ______________________________________                                        Embodiment of the                                                                          ◯                                                                          ◯                                                                          ◯                                                                        ◯                           Invention                                                                     Comparative Example 1                                                                      X        X        X      X                                       Comparative Example 2                                                                      ◯                                                                          ◯                                                                          X      X                                       ______________________________________                                    

Table 3 shows the result of visual clearness of the split margins 19 andfusing areas 21 after deposition.

In this embodiment, the clear margins were recognized by the splitmargins 19 and fuse areas 21 even at a high speed of 600 m/min.

In this embodiment, the metallized film was formed without attaching theimpression roll opposed to the screen cylinder 13 with respect theplastic film 10. The apparatus is preferably provided with an impressioncylinder roll 36. The attachment of the impression roll 36 suppressesthe fluctuation of the plastic film 10 and screen cylinder 13, thusproviding the metallized film with high accuracy. Moving the plasticfilm 10 along the impression roll 36 also realizes the deposition atlike accuracy. If the metallized film should be formed at a highaccuracy, the plastic film 10 is preferably moved along the screencylinder 13. Where it should be formed with an accuracy to a certaindegree at a high speed, the plastic film is preferably moved along theimpression cylinder roll 36.

Like the distance between the screen cylinder 13 and oil nozzle 24 asdescribed above, according to the pattern, the distance adjusting means(not shown) which can form a gap between the screen cylinder 13 and theimpression cylinder roll 36 is preferably provided. In either case, theprovision of the gap is useful for the pattern which intends to diffusethe oil gas.

In the comparative example No. 1 of using the rotary shutter, the rotaryshutter was deformed so that both the split margin areas 19 and the fuseareas could not be almost formed. The deformation of the rotary shutteris due to that the successive area (fuse area) is as thin as 0.8 mm andthe thickness for realizing light weight and low cost was not assuredsufficiently. In the comparative example No. 2 of using the protrusion,at the speed of 600 m/min, metal was partially deposited on the marginso that the metallized film could not have sufficient clearness. This isbecause the oil deposited on the tip of the protrusion is scattered dueto high speed rotation so that a sufficient amount of oil could nottransferred to the film.

In this embodiment, deposition of zinc on the one side was explained.But, the same result was obtained for the deposition of aluminum andalloy of aluminum-zinc, and for both side depositions thereof.

In this way, the above conventional problem can be solved by anapparatus and method for fabricating a metallized film using a vacuumevaporator or evaporation step of forming a metallized film for ametallized film capacitor in the following manner. Specifically, inorder to prevent the evaporated metal from being partially deposited onthe film, vaporized oil gas is previously deposited on the film. Indeposition of the oil gas, any pattern is used which includesthrough-holes (mesh) passing from the surface of the screen cylinder 13having a width larger than that of the plastic film which is a basematerial. While the screen cylinder 13 is rotated in synchronism withthe deposition speed of oil, the vaporized oil is deposited on theplastic film 10 through the through-holes (mesh pattern). Immediatelythereafter, the evaporated metal is deposited on the plastic film.

More specifically, in the evaporator for fabricating a metallized filmfor a capacitor provided with rolls arranged as shown in FIG. 6 and thescreen cylinder 13 as shown in FIG. 8, the gaseous material forpreventing evaporation of metal such as vaporized oil supplied from theoil tank 14 is passed through the screen cylinder 13 having any meshpattern and deposited on the plastic film (dielectric film) 10, andthereafter the metal is deposited thereby making the split fuse patternsand margins having each having a fixed width formed at regularintervals. In addition, the impression roll for defining the path of theplastic film 10 is arranged oppositely to the screen cylinder 13 withrespect to the plastic film 10. For these reasons, even when the oildeposition speed is enhanced, the plastic film 10 does not fluctuate andthe distance between the plastic film 10 and the oil nozzle 24 (oil gasjetting opening), thereby maintaining clearness of the pattern. Further,the screen cylinder, which is light, can be easily exchanged. Since themargins are formed simultaneously with the fuse areas, the exchangeitself can be easily adjusted. Thus, workability can be improved and theapparatus can be made economical.

As understood from the description hitherto made, in accordance withthis embodiment, the split fuse pattern and the margins in thelongitudinal direction which serve as the safeguard mechanism for themetallized film, can be formed during high speed deposition. Thus, themetallized film with excellent safeguard and production can be obtained.The screen cylinder 13, which is lighter than the conventional oilnozzle 24, can be easily removed and attached, and is economical.Accordingly, the apparatus according to the present invention can havegreater total merits than the conventional apparatus.

Additionally, the mesh may include machined through-holes or may befabric.

As described above, in the metallized film capacitor according to thefirst aspect of the present invention, because of electrode partitioninglines formed at regular intervals in a longitudinal direction of a film,where minute breakage which cannot be cleared by self-recovery occurs ina plurality of minute blocks, reduction in capacitance resulting whenthe current flowing from between adjacent minute blocks operates thenon-problematic fuse area between the blocks can be suppressed. Alsowhere the fusing area does not operate because of the short-circuitingcurrent due to clearing of minute breakage, breakage in the capacitorcan be prevented which results from the breakage at the block continuingto lead to dielectric breakdown and to spread toward the surroundingblocks.

The metallized film according to the second aspect of the presentinvention, in addition to the first aspect, has improved the clearing ofthe minute broken area because the minute block in the low resistancefilm area abutting on the electrode lead-out portion has a smaller areathan the other area, thereby improving the operability of the fuse area.For this reason, as regards the breakage which cannot be cleared whenthe evaporated film on the side of the frame sprayed area, theshort-circuiting current continues to flow to prevent the dielectricbreakage from occurring at the thick portion of the evaporated film.

The film capacitor according to the third aspect of the presentinvention, in addition to the second aspect, uses zinc or zinc/aluminumalloy as the evaporated metal. For this reason, using the metalcharacteristic of these metal which require larger energy to performclearing in minute breakage than a single element of aluminum which ismainstream of the metallized film capacitor at present, higher potentialor miniaturization of the metallized film capacitor can be realized thanthe aluminum evaporated capacitor.

As apparent from the description hitherto made, the fourth fabricatingdevice for a metallized film according to the present invention depositsa vaporized metal evaporation preventing agent directly on film througha screen to a clear pattern on a margin at a high speed.

The fifth fabricating device for a metallized film can hold the strengthof the screen to prevent the distortion when the screen is rotated.

The six fabricating device for a metallized film can from a pattern withno clogging accurately.

The seventh fabricating device for a metallized film can hold thevaporized state of a metal evaporation preventing agent until it reachesa film, thereby forming a clear pattern.

The eighth fabricating device for a metallized film makes the shiftingspeeds of a screen and a film synchronous with each other so that thedisplacement or blue of the pattern can be suppressed.

The ninth fabricating device for a metallized film, in which a screen iscylindrical, can easily the screen and will not injure the film.

The tenth fabricating device for a metallized film shifts the film alonga cylindrical face so that the contact between a screen and a film canbe held without using a specific means for holding the film.

The eleventh fabricating device for a metallized film can provide anoptimum distance between a screen and a discharging opening of a metalevaporation preventing agent in accordance with the kind of oil to beused, shifting speed, kind of a pattern, etc.

The twelfth fabricating device for a metallized film can prevent thechattering of a film by an impression cylinder roll, thereby forming apattern accurately.

The thirteenth fabricating device for a metallized film can shift a filmalong the impression cylinder roll so that the film is brought intocontact with the impression roll, thereby keeping the distance betweenthe screen and film.

The fourteenth fabricating device for a metallized film adjusts thedistance between the impression cylinder roll and the screen so that thedistance between the screen and the film can be adjusted.

The fifteenth fabricating device for a metallized film can form a splitmargin and fuse area with no succeeding step.

The method of fabricating a metallized film deposits the vaporized metalevaporation preventing agent directly on a film through a screen to aclear pattern on a margin at a high speed.

The foregoing description of a preferred embodiment of the invention hasbeen presented for purposes of illustration and description. It is notintended to be exhaustive or to limit the invention to the precise formdisclosed, and modifications and variations are possible in light of theabove teachings or may be acquired from practice of the invention. Theembodiment was chosen and described in order to explain the principlesof the invention and its practical application to enable one skilled inthe art to utilize the invention in various embodiments and with variousmodifications as are suited to the particular use contemplated. It isintended that the scope of the invention be defined by the claimsappended hereto, and their equivalents.

What is claimed is:
 1. A device for fabricating a metallized filmcapacitor, comprising:a roll for holding a supply of film; a tank withinwhich a metal deposition preventing agent is vaporized, said metaldeposition preventing agent being effective to prevent evaporated metalfrom being deposited on the film; a cylinder having a side wallcomprising a screen with an evaporation pattern; and a conduit throughwhich said vaporized metal deposition preventing agent is transportedfrom said tank to an interior of said cylinder, thereby causing saidvaporized metal deposition preventing agent to be deposited directly onsaid film through said screen.
 2. A device for fabricating a metallizedfilm capacitor according to claim 1, wherein said screen is a meshhaving openings.
 3. A device for fabricating a metallized film capacitoraccording to claim 2, wherein each of the openings of the mesh has adiameter of 10 gm to 1 mm.
 4. A device for fabricating a metallized filmcapacitor according to claim 1, further comprising temperature-holdingmeans for holding the vaporized state of said metal depositionpreventing agent until said metal deposition preventing agent reachessaid film.
 5. A device for fabricating a metallized film capacitoraccording to claim 1, further comprising means for rotating saidcylinder at a speed in synchronism with the speed of said film.
 6. Adevice for fabricating a metallized film capacitor according to claim 1,wherein said evaporation pattern of said screen has a split margin andfuse portion which constitute a safeguard mechanism.
 7. A device forfabricating a metallized film capacitor according to claim 1, whereinsaid film is transported along a cylindrical face of said cylinder.
 8. Adevice for fabricating a metallized film capacitor according to claim 1,further comprising:a nozzle through which the vaporized metal depositionpreventing agent may be discharged, said nozzle being connected to theconduit and disposed inside the cylinder; and distance adjusting meansfor adjusting a distance between said screen and said nozzle.
 9. Adevice for fabricating a metallized film capacitor according to claim 1,further comprising a roll that cooperates with said cylinder to define apassage through which said tapes moves.
 10. A device for fabricating ametallized film capacitor according to claim 9, wherein said film istransported along a curved surface of said roll.
 11. A device forfabricating a metallized film capacitor according to claim 9, furthercomprising means for adjusting a distance between said roll and saidscreen.